Title: Advanced Composites and Nanodevices Based on Aligned Carbon Nanotubes
Speaker: Xin Wang, Postdoctoral Research Scholar at North Carolina State University
Abstract:
The unique properties of carbon nanotubes (CNTs), such as high strength and stiffness, extremely large specific surface area, low density and high electrical and thermal conductivities, open up opportunities for a wide range of applications. This has led to widespread research on the synthesis of multiscale CNT-based polymeric composites aiming to transfer the intrinsic properties of CNTs from nanoscale to macroscale. Currently known conventional methods for producing CNT composites rely on dispersing short nanotubes in polymer matrices or infiltrating CNT “buckypaper” with resins. However, despite extensive worldwide effort, it has been a challenge for two decades to assemble the extremely strong carbon nanotubes into macroscopic CNT composites that break the strength ceiling of carbon fiber composites. Our recent work shows that by stretching aligned carbon nanotubes before embedding them into polymer matrix, CNT composites have achieved unprecedented multifunctionalities, including record high tensile strength (3.8 GPa), Young’s modulus (293 GPa), electrical conductivity (1230 S cm-1) and thermal conductivity (40 W m-1 K-1). The combined strength and stiffness have exceeded those of carbon fiber composites. Our observation suggests that the strengthening and conducting mechanism is derived from the synergistic effect of high degree of CNT alignment, long CNT length, high volume fraction and uniform distribution of CNTs in the polymer matrix produced by the novel “stretch-winding” approach. I will also discuss our recent work and collaborative work on aligned-CNT-based functional polymer composites, stretchable conductors, strain sensors and biosensors.